Sustaining the source and flow of life forever

Transcription

1 Sustaining the source and flow of life forever WATER IN OUR LIVES!

2 THE ROLE OF WATER IN OUR LIVES When many of us think about water, we think of fun and having a good time. However, the role of water in our lives goes far beyond recreation and relaxation. We need water to prepare and cook food. Without water we cannot wash our hands and bodies. Water is used to do our washing and ensure that we wear clean clothes. Water is needed to flush toilets and promote hygiene. Vegetables, that we eat to stay healthy, require water to grow. And not forgetting that, we as human beings, cannot survive without water. We can live for up to three weeks without food, but we will die within 3-5 days if we do not drink water or take in other water-based fluids. Therefore, we cannot do without water in our lives! We use water for so many purposes in our lives 2

3 WELCOME TO SEDIBENG WATER Sedibeng Water is situated at Balkfontein, just outside Bothaville in the Free State Province Sedibeng Water is the water services provider in your area. We were established in 1979, mainly to serve the Free State Goldfields and parts of the former Western Transvaal. Sedibeng Water currently services an operational area spanning across 3 provinces: Free State, North West and Northern Cape. This makes Sedibeng Water one of the largest water utilities in the country. We are supplying water to municipalities, farmers, industries and mines. Our water is used by industries to cool down machinery. Without water, many mining activities will not be possible. And some municipalities also use us to provide drinking water to their communities. Every year, we provide about 120 million kiloliters of water to our clients and consumers. So, Sedibeng Water plays a very important role in not only promoting economic activities, but also putting water in the taps of many communities. We have compiled this booklet to demonstrate to you how, and why we do what we do at Sedibeng Water. We will give attention to the water cycle, how water gets to your tap and the water treatment process. We will also highlight the important contribution that our Department of Scientific Services makes in everyday activities at Sedibeng Water. 3

4 THE WATER CYCLE Water is a scarce resource. Let s say that all the water on earth is equal to 100%. Of all the water available, 97% is water that we find in the oceans. Unfortunately, we cannot drink salt water. That leaves us with about 3% fresh water that we can use. But where does this available surface water come from? It happens like this: Every day the sun heats the water in the sea. A lot of water then evaporates - that is, it turns into gas or water vapour. Transpiration by plants also takes place. Rain will run eventually in streams into a dam or a river and then back into the sea. THE WATER CYCLE When there are enough clouds, these water drops will fall to the earth as rain, which is also known as precipitation. Water vapour raises and forms clouds of moist air. The wind blows the clouds over land and condensation takes place. Condensation is when water drops in the clouds are formed from water vapour. And then the entire process starts again. Water in rivers eventually flows into the sea. The heat of the sun causes evaporation. Condensation takes place in the clouds, followed by precipitation or rain. This entire process is called the water cycle, because it happens over and over again. 4

5 HOW WATER GETS TO YOUR TAP The water cycle explains where the water that we use comes from, but how does it get to your tap? Not by itself. It takes a long and expensive process to bring water to our communities. This is how it happens: Some of the surface water flowing in rivers is caught up in dams to stop it all from flowing into the sea. Water is then pumped from such a dam (or directly from a river) to treatment works where the water is treated (that is cleaned) so that it is safe to drink and use. From the treatment works the water is pumped to reservoirs. Reservoirs are tanks in various forms where huge amounts of clean water can be stored. Pipelines run from the reservoirs to communities where taps are connected to a network of underground water pipes. The process of bringing water to your tap can be visualised as follows: Raw water in a river Water extracted from a river Water being treated at a treatment plant Pump station distributing clean water Clean water for you to use and enjoy! Taps connected to pipeline network Pipelines bring water to your home Water stored in reservoirs As you can see from the above, it takes a lot of effort and infrastructure to supply water to communities. 5

6 THE WATER TREATMENT PROCESS STEPS IN WATER TREATMENT RAW AND UNTREATED WATER DESTABILISATION FLOCCULATION SEDIMENTATION Filtration DISINFECTION STABILISATION CLEAN AND TREATED WATER (Simplified illustration) 6

7 Our water treatment plant at Balkfontein We cannot drink water straight from a dam or river. We must clean or treat the water first. The reason is that the water from a river or dam is often dirty and polluted with dangerous or poisonous substances. Many of the small organisms such as parasites, bacteria and viruses that live and grow in polluted water, can also be very harmful to us. To treat water and make it safe to drink and use, is quite a complicated process. It consists of the following 6 steps: Step 1: Destabilisation First, the water is pumped from the dam or river to the treatment plant. At this stage, the electrical charge of each of the tiny bits or particles of dirt hanging in the water, is negative and therefore they repel one another. A chemical, such as Ferric Chloride for example, is now mixed into the dirty water. Ferric Chloride changes the electrical charge of the dirt particles in the water from negative to neutral, so that these particles will no longer repel one another. This process is called destabilisation. From here, the destabilised water flows to the next phase in the treatment process. Tanks containing Ferric Chloride to destabilise raw water Ferric Chloride being mixed into raw water 7

8 Step 2: Flocculation It is important that the dirty water must now run slowly. A network of channels, that gradually becomes deeper and wider, is used for this purpose. Since their charge is neutral, the dirt particles hanging in the slow flowing water will now cling to one another. As you can see in the flask below, the neutral dirt particles collide and form larger particles. This process is called flocculation. Destabilisation (step 1) and flocculation (step 2) is also known as coagulation. Channels with slow flowing water to promote flocculation Flocculation taking place Step 3: Sedimentation This step takes place in tanks that are about 8 metres deep. Here, larger and heavier dirt particles in the water sink to the bottom to form a sediment or sludge that is removed daily. By now the water is much cleaner and about 90% of the dirt has been removed. Sedimentation taking place, is demonstrated in the flask below. However, water coming from sedimentation tanks is not yet fit for human consumption. Sedimentation tanks Sedimentation taking place 8

9 Step 4: Filtration The next step is to filter the water. Water flows from the sedimentation tanks to a filtering facility. Several filter units, which are about 0,75 to 1 meter deep, is used for this purpose. At the bottom of each filter unit are nozzles through which air and clean water are blown to clean the unit when necessary. On top of the nozzles are a 250 mm layer of gravel and a 750 mm layer of a very special kind of sand. When water passes through the layer of sand, dirt particles are prevented from flowing through. Water that comes out of the filtration unit is more clear, but still not safe to drink and use. A special kind of sand used for filtering Filter units Step 5: Disinfection Some dangerous organisms in water are so small that they pass through the sand during the filtration process. The only way to get rid of such organisms is to kill them by using a disinfectant called chlorine. Chlorine vanishes almost immediately after it has killed these organisms. Although it leaves somewhat of a taste, chlorine that remains behind in the water is harmless to people and animals. During the entire process, the amount of chlorine used is monitored and regulated. Only now is the water safe to drink and use. Water after filtering looks clean, but is not yet safe to drink Controlling the amount of chlorine needed to clean water 9

10 Step 6: Stabilisation The last step in the purification process is to stabilise the water. For this purpose, lime is used. Water that is not stabilised with lime causes rust and breakages in pipes. Only after stabilisation, is the water pumped to reservoirs or tanks where it is stored and ready for use. Some of the underground pipelines to reservoirs could be hundreds of kilometres long and it is costing millions of rands to build and maintain such pipeline networks. A Lime saturator used to stabilise water Underground pipeline networks Water reservoirs used to store clean water 10

11 THE ROLE OF OUR DEPARTMENT OF SCIENTIFIC SERVICES At Sedibeng Water it is the task of our laboratory, that forms part of our Department of Scientific Services, to monitor if the water we provide to municipalities, communities and other clients is safe to use. This laboratory employs highly trained scientists that ensure the purification processes at our various treatment works meet all requirements. When water quality is not up to standard, they immediately take steps to rectify the situation. Testing and analysing the quality of water using scientific procedures and specialised equipment IN CONCLUSION In conclusion, we at Sedibeng Water trust that you have enjoyed reading this booklet and that you now have a better understanding of the provision and treatment of water. We also hope that you have more insight into the role that Sedibeng Water and its Department of Scientific Services play in bringing safe drinking water to your tap. Always remember never drink water from a dam or river that has not been treated. And... conserve water, it is a scarce resource! 11

12 Regional and District Offices: CONTACT INFORMATION Should you need more information on Sedibeng Water, please contact us at: Head Office: Protea Street, Balkfontein, Bothaville, 9660 Private Bag X5, Bothaville, 9660, South Africa Tel: / Fax: GPS Co-ordinates: S E ceosec@sedibengwater.co.za VIRGINIA (FREE STATE REGION) P.O. Box 518, Virginia, 9430 GPS Co-ordinates: S E Tel: , or Fax: HARTSWATER (NORTH WEST REGION) Private Bag X2, Hartswater, 8570 GPS Co-ordinates: S E Tel: /0142 / Fax: MOTHIBISTAD (NORTH WEST REGION) P.O. Box 386, Mothibistad, 8474 GPS Co-ordinates: S E Tel: / Fax: LEHURUTSHE (NORTH WEST REGION) P.O. Box 58, Mahikeng, 2745 GPS Co-ordinates: S E Tel: or Fax: MONTSHIOA (NORTH WEST REGION) P.O. Box 58, Montshioa, Mahikeng, 2745 GPS Co-ordinates: S E Tel: /3 or Fax: VAAL GAMAGARA (NORTHERN CAPE REGION) Private Bag X1, Delportshoop, 8377 GPS Co-ordinates: S E Tel: / Fax: March 2017 Edition TAUNG (NORTH WEST REGION) P.O. Box 2073, Taung Station, 8580 GPS Co-ordinates: S E Taung Cash point: Tel: Fax: Taung District office: MMABATHO (NORTH WEST REGION) P.O. Box 4500, Mmabatho, 2735 GPS Co-ordinates: S E Tel: /3 or /50 Fax: GANYESA (NORTH WEST REGION) Private Bag X523, Ganyesa, 8613 GPS Co-ordinates: S E Tel: / Fax: NAMAKWA - SPRINGBOK (NORTHERN CAPE REGION) Private Bag X39, Springbok, 8240 GPS Co-ordinates: S E Tel: , or Fax: NAMAKWA - PELLADRIFT (NORTHERN CAPE REGION) Private Bag X39, Springbok, 8240 GPS Co-ordinates: S E Tel: , or Fax: